Internal combustion engine



FIG. 1 is a front perspective view of an internal combustion engine showing our new design;

FIG. 2 is a rear perspective view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a left side elevational view thereof;

FIG. 6 is a right side elevational view thereof;

FIG. 7 is a top plan view thereof; and,

FIG. 8 is a bottom plan view thereof.

The broken lines illustrate structure or features which form no part of the claimed design. 

CLAIM The ornamental design for an internal combustion engine, as shown and described. 